The present disclosure relates generally to the calibration of video camera views. More specifically, the present disclosure relates to targets used for remote alignment of cameras, such as in a video conference room.
Video conference systems that use specially-configured video conference studios have been developed to provide the look and feel of a face-to-face conference. Such systems can include a pair (or more) of specially-configured video conference studios that each include seating places for multiple persons facing one or more video conference displays. One or more video conference cameras take images of the persons in each room, and provide the respective images to corresponding video displays in the other video conference studios, wherever they are located. In this type of video conference arrangement, the participants can see and hear the other participants as if they were all together in the same room. These types of video conference systems are sometimes referred to as “remote presence” or “telepresence” video conference systems. With the video conference cameras properly oriented and a suitable background in each conference room, this configuration can provide a blended video conference environment that approximates the appearance of a face-to-face conference session.
One potentially time-consuming and expensive process that can be associated with remote presence video conference systems is the alignment and calibration of the video cameras. The video cameras in specially-configured video conference studios can each include a pan-tilt-roll (PTR) mechanism, which allows the orientation and alignment of each camera to be adjusted. Mechanical adjustment of the camera alignment, along with adjustment of the zoom and focus controls of the camera itself, allows the camera to provide different views. For example, in some instances it can be desirable for a given camera to view three or more participant positions in the conference room, while at other times it may be desired for the same camera to be adjusted to view only one or two participant positions. This process typically requires someone in the room to help set up alignment targets or marks in specific locations of the room so that a remote person can perform the calibration. After the alignment is finished, the marks are removed. Once a room is in a production state, if there is a problem with the view of any given camera, a person must go back to the room to replace the targets to help realign the cameras.